Persistent/progressive subclinical contrast-induced nephropathy – predictors and effects of parenteral hydration. A prospective study in patients undergoing coronary angioplasty

Abstract

Abstract Background In most cases, contrast-induced nephropathy (CIN) appears to be a transient event. The pathophysiology of CIN, which includes renal vasoconstriction and hypoxia, generation of cytotoxic reactive oxygen species, and even direct tubular toxicity, suggests however that the tubular impairment typical for CIN may not be entirely transient and that persistent/progressive subclinical kidney dysfunction could actually occur. Purpose We aimed to evaluate the incidence, identify the predictors, and assess the impact of parenteral hydration on the occurrence of persistent/progressive subclinical CIN in patients undergoing coronary angioplasty. Methods A total of 71 patients scheduled for elective coronary angioplasty were randomized into two groups: Control (n=36) and HYD (n=35). Patients in the HYD group received prophylactic hydration with saline solution (1 ml/kg/h; 6 h prior to and 12 h after the procedure). Plasma levels of neutrophil gelatinase-associated lipocalin (NGAL), a specific marker of tubular impairment, were evaluated prior to, and 48 h and 1 month after the angioplasty procedure. Persistent/progressive subclinical CIN at 1 month post-angioplasty was defined as a significant increase in NGAL at 48 h after the procedure that persisted (i.e., did not change by more than 10%) or aggravated (i.e., increased by more than 10%) at 1 month follow-up. The ability of several factors (i.e., age, hypertension, diabetes, use of nephrotoxic drugs, baseline creatinine clearance, volume of contrast agent) to predict persistent/progressive CIN was evaluated. The ability of parenteral hydration to prevent persistent/progressive CIN was also assessed. Results According to the current criteria, CIN was present in 5 (7.0%) patients. Meanwhile, subclinical CIN was identified in 36 (50.7%) patients, of which 10 (27.7%) presented persistent and 15 (41.6%) progressive CIN at 1 month follow-up. The volume of contrast administered during angioplasty was the only factor that differed significantly between patients who developed persistent/progressive CIN and those who did not (178±17 mL vs. 130±10 mL, p=0.01). In ROC analysis, contrast volume ≥150 mL predicted persistent/progressive CIN with 77% sensitivity and 60% specificity (p<0.001). Prophylactic hydration was associated with a 75% lower risk of persistent/progressive CIN (RR 0.25; 95% CI 0.09–0.65; p=0.001). Conclusions Despite the relatively low incidence of CIN, subclinical CIN was identified in more than 50% of the study patients. More than 2/3 of these patients presented persistent or progressive subclinical CIN at 1 month follow-up. The clinical impact of this persistent/progressive subclinical CIN in patients undergoing multiple contrast administrations remains to be established. Our data indicate that reducing the contrast volume and/or using prophylactic parenteral hydration can significantly reduce persistent/progressive subclinical CIN. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by a grant of the Romanian Ministry of Education and Research, CNCS-UEFISCDI